include/gc_alloc.h

@@ -0,0 +1,19 @@
+#ifndef GC_ALLOC_H
+#define GC_ALLOC_H
+
+#include <stdio.h>
+
+// Metadata for allocated memory
+struct gc_block_header {
+	size_t size;
+	int free;
+	struct gc_block_header *next;
+};
+
+// Performs allocations of SIZE bytes
+void *gc_malloc(size_t size);
+
+// Frees blocks of memory allocated by 'gc_alloc'
+void gc_free(void *ptr);
+
+#endif /* GC_ALLOC_H */

include/gc_malloc.h

@@ -1,51 +0,0 @@
-#ifndef GC_MALLOC_H
-#define GC_MALLOC_H
-
-#include <stdint.h>
-#include <unistd.h>
-
-// Generally, inline functions are preferable to macros resembling functions.
-// https://www.kernel.org/doc/html/v4.10/process/coding-style.html#data-structures
-
-#define OVERHEAD 1 /* Number of 8-byte segments for chunk size & flags */
-#define MAGIC 2 /* Number of 8-byte segments from top of chunk to fields */
-#define MIN 3 /* Minimum number of 8-byte segments for data in a chunk */
-
-/*
- * Metadata and user data for allocated memory
- *
- * footer: user data for previous chunk
- * size: size of chunk in bytes
- * merge: flag to identify when the chunk can be coalesced
- * free: flag to identify when the chunk is free
- * next: pointer to next chunk in the free list
- * prev: pointer to previous chunk in the free list
- */
-struct gc_chunk {
-	uint64_t footer;
-	uint32_t size;
-	uint16_t merge;
-	uint16_t free;
-	struct gc_chunk *next;
-	struct gc_chunk *prev;
-};
-
-// Gets a pointer to the next chunk
-struct gc_chunk *get_next_chunk(struct gc_chunk *curr);
-
-// Gets a pointer to the previous chunk, ensuring that current can be coalesced
-struct gc_chunk *get_prev_chunk(struct gc_chunk *curr);
-
-// Updates chunk footer information
-void set_footer(struct gc_chunk *curr);
-
-// Gets footer information for the current chunk
-int get_footer(struct gc_chunk *curr);
-
-// Performs allocations of SIZE bytes
-void *gc_malloc(size_t size);
-
-// Frees blocks of memory allocated by 'gc_alloc'
-void gc_free(void *ptr);
-
-#endif /* GC_MALLOC_H */

src/gc_alloc.c

@@ -0,0 +1,2 @@
+#include "gc_alloc.h"
+

src/gc_malloc.c

@@ -1,42 +0,0 @@
-#include <assert.h>
-#include <stdint.h>
-#include <sys/mman.h>
-
-#include "gc_malloc.h"
-
-// Hides chunk header
-static inline void *hide(struct gc_chunk *curr)
-{
-	return (void *)((uint64_t *)curr + MAGIC);
-}
-
-// Reveals chunk header
-static inline struct gc_chunk *magic(void *mem)
-{
-	return (struct gc_chunk *)((uint64_t *)mem - MAGIC);
-}
-
-// Aligns the amount of memory requested by the user with chunk size
-static inline size_t align(size_t size)
-{
-	const size_t alignment = 8;
-	size = (size + (alignment - 1)) & ~(alignment - 1);
-
-	if (size <= MIN)
-		return MIN;
-	else
-		return size;
-}
-
-struct gc_chunk *get_next_chunk(struct gc_chunk *curr)
-{
-	unsigned size = curr->size;
-	return (struct gc_chunk *)((uint64_t *)curr + MAGIC + (size - 1));
-}
-
-struct gc_chunk *get_prev_chunk(struct gc_chunk *curr)
-{
-	assert(curr->merge);
-	unsigned size = curr->footer;
-	return (struct gc_chunk *)((uint64_t *)curr - (size - 1) - MAGIC);
-}